Plasmid Profile of Antibiotic Resistant Escherichia Coli Isolated from Chicken Intestines‪.‬

ABSTRACT Fifty-seven strains of Escherichia coli from chicken intestines were isolated and tested against 15 antibiotics by the disk diffusion method. All strains were resistant to at least one of the tested antibiotics. Resistance to 12 antibiotics was the maximum observed. 26.3% of the isolates exhibited multiple resistances to 50% of the tested antibiotics. Most of the isolates were resistant to tetracycline and nalidixic acid. R-plasmids were extracted and separated by agarose gel electrophoresis for profiling. Plasmid profiling of antibiotic resistant Escherichia coli isolates revealed that the isolates contained various size R-plasmids. Although some strains exhibited different antibiotic resistance patterns, some of their plasmids had similar migration patterns on agarose gel electrophoresis. Multiple resistances are conferred by R-plasmids of different sizes. The high prevalence of antibiotic resistance conferring plasmids observed in this study may be due to the increasing widespread use of antibiotics.